Not pithy, this sharp new saw. Just as there's nothing pithy about the complicated muddle that we, the hopeful consumers of fresh fish, face staring down at the fish-laden beds of crushed ice at the local seafood counter.
What's the muddle?
Fish are good for you, right? Particularly oily fish with their high ration of omega-3 fatty acids. But, they're endangered. And now we're learning that fish oil may be an efficient delivery system of environmental poisons. World fish stocks are in scarily terrible shape and getting worse. But that's OK; we're moving away from wild harvesting to domesticated fish farming. Indeed, the farmed share of the world fish harvest has gone, in just over 30 years, from under 4 percent to almost 30 percent. And 80 percent of salmon is farmed.
And that's a good thing, right?
By and large, no. It hasn't really taken any pressure off the wild harvest, except for the rare spots where complex conservation efforts have been mobilized. Fish-farming has recapitulated the dismal centuries-long history of agricultural farming--but compressed it into a half-century of industrialization and ecological disaster. Modern fish-farming has many of the appealing features of modern hog farming, right down to waste lagoons, close confinement, drugs to combat the effects of confinement, bad genetics, habitat loss and "efficiencies of scale."
"Aquaculture," as it is uncharmingly neologized, has all these problems of modern industrial agriculture and then some. What's the "then some"? PCBs and mercury, although those may only be the chemical canaries in this seafood minefield.
(Don't get too depressed about fish in your diet. I have some useful specifics at the end.)
Let's parcel out the problems.
The world fish population has been crashing. Major food fish--cod, swordfish, tuna and others--have been in trouble for a while. (Cod, by Mark Kurlansky, is a now classic work on the history of the cod's fortune. Swordfish is following in cod's ghostly wake--what used to count as a medium-sized fish is now as big as it gets.) Much of this is from overfishing, as fish-catching technology has allowed for huge harvests. Some of these technologies, in addition to the sheer size of the catch they enable, have side effects that involve disruption of the marine habitat and the infamous bycatch, which kills non-targeted fish, caught up in the net or line, that are regarded as trash. (Monkfish used to be regarded, in the United States, as bycatch. Then it got popular, and is now endangered and on most "red" lists.)
What overfishing doesn't decimate, pollution does. As massive as the oceans are, we have managed to almost destroy them. The majority of pollution is landbased--agricultural run-off, industrial waste and the like.
Global wild fish catch tonnage itself hasn't started to decline yet. But that's only because technology, and the huge overcapacity of the fishing industry, has been able to reach into the oceans more broadly and deeply than ever before. But this also means reaching lower and lower into the food chain, which just shortens the time to doomsday.
As a special bonus, some of this pollution doesn't kill the fish. It just kills us. Both mercury pollution and PCB pollution have been in the news lately. It turns out that large fish, high up in the food chain, are efficient concentrators of environmental poisons. PCBs have even been found in isolated and pristine subarctic freshwater lakes, brought there in the bodies of Pacific salmon, who came to spawn and die.
Shark, swordfish, tilefish and king mackerel are high-mercury fish, which the FDA warns childbearers, nursing women and young children not to eat. In North Carolina, largemouth bass, jackfish and blackfish (I'm quoting from the federal advisory) "caught east and south of Interstate 85 ... may contain unsafe levels of mercury." The FDA does want you to eat fish, so it advises that shrimp, canned light tuna (not white), salmon, pollock and catfish are low in mercury. But, salmon and other farmed fish have problems all their own.
You might think that farmed fish would have fewer problems due to pollution, because of the greater control of their environment. In theory. In fact, they produce a lot of hog-farm-style pollution of their own. Additionally, their crowded conditions, just as on land, require the ameliorating effects of antibiotics and the various "cides"--pesticides, algaecides, etc. In particular, there are reasons to worry about the pesticides used against fish lice, which hit crustacean populations particularly hard.
Not to mention that, if you're worried about the viability of the wild populations, escapees from the farm are a real genetic worry. The fancy word is "introgression." When responsible hatcheries try to develop broodstocks of salmon to release into the wild, they worry a lot about using the right local populations for breeding, as well as the timing of releases. With escapees, bred for rapid growth and tolerance of crowding, all such caution is nil. Instead of saving wild populations, fish farms do (though they needn't) introduce competitors, disease and pollution to their wild neighborhood.
And, of course, the big news from January, from an article in Science, was the high levels of PCBs in most farmed salmon, often as much as 10 times that found in wild salmon. Now, the industry flack like to point out that the levels were within FDA tolerances, and that you would want to trade off the increase in cancer against the positive health effects of those omega-3s. Well, those levels are outside EPA tolerances and would prompt FDA warnings about consumption if the fish were caught recreationally. The FDA's higher tolerance comes from their mandate to balance health effects against commercial interests when regulating "caught" versus "bought."
Curiously, it was European farm-raised salmon, including the pristine sounding Icelandic, that was particularly high in PCBs. Scottish salmon was notably bad. Chilean salmon actually did best among the farm-raised. Where do the PCBs come from? The food fed to the fish; which, for these carnivores is fishmeal. (You don't, by the way, want to live next to a fishmeal factory.) So that's where some wild catch goes, into mouths of farm salmon. The yields here are low. It takes 4 or 5 tons of small pulverized fish to make 1 ton of farmed shrimp or salmon.
But you don't have to buy into the false dichotomy of farmed omega-3s or mad cow; we are free to wait for wild Alaskan salmon, which both tastes better and isn't PCB-rich. And yes, that means not eating salmon year-round (though there is frozen Alaskan salmon).
So, think of salmon as another seasonal food, like tomatoes. The ubiquity of salmon is a recent invention. Our top three seafoods used to be shrimp, canned tuna and fish sticks. Now they're shrimp, canned tuna and "fresh" salmon.
It's also worth pointing out that we have a coastline not too far away and local fish, such as porgy and flounder, that are available from local seafood markets like Earp's in Raleigh, Leo's in Durham and Tom Robinson's in Carrboro.
So that's a start on unmuddling. Eat locally and eat wild--but responsibly.